Seoul -- South Korea flexed its military muscle Thursday by staging large military drills and disclosing a new cruise missile capable of hitting any target in North Korea, as the North became increasingly candid about its intentions to build intercontinental ballistic missiles tipped with nuclear warheads.

"We no longer hide but publicly declare: If the imperialists have nuclear weapons, we must have them, and if they have intercontinental ballistic missiles, we must have them, too," the North's state-run Rodong Sinmun newspaper, the most authoritative mouthpiece for the North's leadership, said in a commentary published Thursday. "Anger seeks weapons."

"Imperialist" is the word that North Korea uses to refer to the United States.

Washington and its allies have condemned North Korea's launching of a satellite in December and its underground nuclear test Tuesday as a cover for developing nuclear-tipped ballistic missiles capable of reaching North America. But only recently did the North begin publicly indicating that it intended to build such missiles.

On Jan. 24, it said that Washington's hostilities, which it said were behind U.N. sanctions against the country, were forcing it to redirect its rocket and nuclear programs to "target against the U.S."

Although blustering is a common propaganda trope for North Korea, its increasingly public boasting comes amid growing concerns among the governments in the region that North Korea was moving closer to building workable long-range nuclear missiles. If unchecked, U.S. officials feared, the North's drive would embolden Iran to pursue its own nuclear ambitions despite stiff sanctions.

"It's important for the world to have credibility with respect to our nonproliferation efforts," Secretary of State John Kerry said Wednesday in urging the world to make a "swift, clear, strong and credible response" to the North's third nuclear test. "What our response is with respect to this will have an impact on all other nonproliferation efforts."

South Korea's reaction has been swift. On Thursday, its political parties put aside their bickering over domestic politics and passed nearly unanimously a parliamentary resolution condemning the North's nuclear test. Its navy deployed destroyers and submarines off its eastern coast to test their combat readiness.

South Korea started a similar naval drill off the western coast Wednesday and planned Friday to begin live-fire drills involving rockets and artillery near the land border with North Korea. The U.S. military, which keeps 28,500 troops in South Korea, was staging an air drill mobilizing jet fighters of the two allies.